Chemistry Class 12

Chemistry Class 12 Chapter 12 objective

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Aldehydes, Ketones and Carboxylic Acids Objective Questions

  1. Benzoyl chloride on reduction with H2/Pd-BaSO4produces

(A) benzoic acid

(B) benzyl alcohol

(C) benzoyl sulphate

(D) benzaldehyde

Ans (D) benzaldehyde

  1. There is a large difference in the boiling points of butanal and butan-l-ol due to

(A) intermolecular hydrogen bonding in butan-l-ol

(B) intramolecular hydrogen bonding in butanal

(C) higher molecular mass of butan-l-ol

(D) resonance shown by butanal

Ans (A) intermolecular hydrogen bonding in butan-l-ol

  1. Arrange the following compounds in increasing order of their reactivity in nucleophilic addition reactions. Ethanal, Propanal, Propanone, Butanone

(A) Butanone < Propanone < Propanal < Ethanal

(B) Propanone < Butanone < Ethanal < Propanal

(C) Propanal < Ethanal < Propanone < Butanone

(D) Ethanal < Propanal < Propanone < Butanone

Ans (A) Butanone < Propanone < Propanal < Ethanal

  1. Which among the following is most reactive to give nucleophilic addition ?

(A) FCH2CHO

(B) CICH2CHO

(C) BrCH2CHO

(D) ICH2CHO

Ans (A) FCH2CHO

  1. The addition of HCN to carbonyl compounds is an example of

(A) nucleophilic addition

(B) electrophilic addition

(C) free readical addition

(D) electromeric addition

Ans (A) nucleophilic addition

  1. Which of the following compounds does not react with NaHS03?

(A) HCHO

(B) C6H5COCH3

(C) CH3COCH3

(D) CH3CHO

Ans (B) C6H5COCH3

  1. Aldehydes other than formaldehyde react with Grignard’s reagent to give addition products which on hydrolysis give

(A) tertiary alcohols

(B) secondary alcohols

(C) primary alcohols

(D) carboxylic acids

Ans (B) secondary alcohols

  1. What is the test to differentiate between pentan-2-one and pentan-3-one ?

(A) Iodoform test

(B) Benedict’s test

(C) Fehling’s test

(D) Aldol condensation

Ans (A) Iodoform test

  1. The best oxidising agent for oxidation of

CH — CH = CH — CHO to CH3 — CH = CH — COOH is

(A) Baeyer’s reagent

(B) Tollen’s reagent

(C) Schiff s reagent

(D) acidified dichromate

Ans (B) Tollen’s reagent

  1. Which of the following does not answer iodoform test ?

(A) n-Butyl alcohol

(B) sec-Butyl alcohol

(C) Acetophenone

(D) Acetaldehyde

Ans (A) n-Butyl alcohol

  1. To differentiate between pentan-2-one and pentan-3-one a test is carried out. Which of the following is the correct answer ?

(A) Pentan-2-one will give silver mirror test

(B) Pentan-2-one will give iodoform test

(C) Pentan-3-one will give iodoform test

(D) None of these

Ans (B) Pentan-2-one will give iodoform test

  1. Which of the following will not give aldol condensation ?

(A) Phenyl acetaldehyde

(B) 2-Methylpentanal

(C) Benzaldehyde

(D) I-Phenylpropanone

Ans (C) Benzaldehyde

  1. Propanal on treatment with dilute sodium hydroxide gives

(A) CH3CH2CH2CH2CH2CHO

(B) CH3CH2CH(OH)CH2CH2CHO

(C) CH3CH2CH(OH)CH(CH3)CHO

(D) CH3CH2COOH

Ans (C) CH3CH2CH(OH)CH(CH3)CHO

  1. When propanal reacts with 2-methylpropanal in presence of NaOH, four different products are formed. The reaction is known as

(A) aldol condensation

(B) cross aldol condensation

(C) Cannizzaro reaction

(D) HVZ condensation

Ans (B) cross aldol condensation

  1. Which compound is obtained when acetaldehyde is treated with dilute solution of caustic soda ?

(A) Sodium acetate

(B) Resinous mass

(C) Aldol

(D) Ethyl acetate

Ans (C) Aldol

  1. Which of the following compound will undergo self aldol condensation in the presence of cold dilute alkali ?

(A) CH ≡ C – CHO

(B) CH2 = CHCHO

(C) C6H5CHO

(D) CH3CH,CHO

Ans (D) CH3CH,CHO

  1. Which of the following compounds will undergo Cannizzaro reaction ?

(A) CH3CHO

(B) CH3COCH3

(C) C6H5CHO

(D) C6H5CH2CHO

Ans (C) C6HsCHO

  1. Which of the following does not undergo Cannizao’s recations ?

(A) Benzaldehyde

(B) 2-Methylpropanal

(C) p-Methoxybenzaldehyde

(D) 2,2-Dimethylpropanal

Ans (B) 2-Methylpropanal

  1. Which of the following aldehydes will show Cannizzaro reaction ?

(A)HCHO

(B)C6H5CHO

(C) (CH3)3CCHO

(D) All of these

Ans (D) All of these

  1. What are the correct steps to convert acetaldehyde to acetone ?

(A) CH3MgBr, H2O, Oxidation

(B) Oxidation, Ca(OH)2, Heat

(C) Reduction, KCN, Hydrolysis

(D) Oxidation, C2H5ONa, Heat

Ans (B) Oxidation, Ca(OH) 2, Heat

  1. Which of the following will not yield acetic acid on strong oxidation ?

(A) Butanone

(B) Propanone

(C) Ethyl ethanoate

(D) Ethanol

Ans (C) Ethyl ethanoate

  1. Carboxylic acids dimerise due to

(A) high molecular weight

(B) coordinate bonding

(C) intermolecular hydrogen bonding

(D) covalent bonding

Ans (C) intermolecular hydrogen bonding

  1. Which of the following earboxylic acids is highly insoluble in water ?

(A) Propanoic acid

(B) Butanoic acid

(C) Pentanoic acid

(D) Decanoic acid

Ans (D) Decanoic acid

  • Which of the following is the correct order of relative strength of acids ?

(A) ClCH2COOH > BiCH2COOH > FCH2COOH

(B) BrCH2COOH > ClCH2COOH > FCH2COOH

(C) FCH2COOH > ClCH2COOH > BrCH2COOH

(D) ClCH2COOH > FCH2COOH > BrCH2COOH

Ans (C) FCH2COOH > ClCH2COOH > BrCH2COOH

  1. What happens when a carboxylic acid is treated with lithium aluminium hydride ?

(A) Aldehyde is formed

(B) Primary alcohol is formed

(C) Ketone is formed

(D) Grignard reagent is formed

Ans (B) Primary alcohol is formed

  1. Which of the following will not undergo HVZ reaction ?

(A) Propanoic acid

(B) Ethanoic acid

(C) 2-Methylpropanoic acid

(D) 2, 2-Dimethylpropanoic acid

Ans (D) 2, 2-Dimethylpropanoic acid

  1. Which of the following statements is correct regarding formic acid ?

(A) It is a reducing agent

(B) It is a weaker acid than acetic acid

(C) It is an oxidising agent

(D) When its calcium salt is heated, it forms acetone

Ans (A) It is a reducing agent

  1. The correct order of increasing acidic strength is…..

(A) phenol < ethanol < chloroacetic acid < acetic acid

(B) ethanol < phenol < chloroacetic acid < acetic acid

(C) ethanol < phenol < acetic acid < chloroacetic acid

(D) chloroacetic acid < acetic acid < phenol < ethanol

Ans (C) ethanol < phenol < acetic acid < chloroacetic acid

  1. The reagent which does not react with both, acetone and benzaldehyde is……..

(A) sodium hydrogensulphite

(B) phenyl hydrazine

(C) Fehling’s solution

(D) Grignard reagent

Ans (C) Fehling’s solution

  1. Which of the following compounds will give butanone on oxidation with alkaline KMnO4solution ?

(A) Butan-l-ol

(B) Butan-2-ol

(C) Both of these

(D) None of these

Ans (B) Butan-2-ol

  1. In Clemmensen reduction carbonyl compound is treated with……….

(A) zinc amalgam + HCl

(B) sodium amalgam + HCl

(C) zinc amalgam + nitric acid

(D) sodium amalgam + HNO3

Ans (A) zinc amalgam + HCl

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